Copper base alloy



, alloy including tin and this latter alloy plus manundesirable.

Patented Feb. 18, 1936 UNITED STATES PATENT ornea Herbert c. Jennison, Bridgeport, Conn., assign...

to The American Brass Company, Waterbury, Coma, a corporation of Connecticut No Drawing. Original application August 5, 1938,

Serial No. 683,907. Divided and this application July 30, 1935, Serial No. 33,831

8 Claims. (Cl. (5-1) This invention relates to alloys containing high percentages of copper which are capable of being hardened by certain processes of heat treatment,

and more particularly copper base alloys containtreatment and a method or process of improving the resulting product.

This application is a division of my prior application Serial Number 683,907, filed August 5, 1933, for Copper base alloy, and is directed to the ganese.

In the patent to Corson 1,658,186 issued February '7, 1928, is described a process of heat treatment of copper base alloys containing certain amounts of silicon and nickel which comprises heating the alloy to a high temperature (from 750 to 975 C.) and holding it there for a given time, then quenching and reheating to a temperature 01' between 250 C. and 600 C. and holding at this temperature for a given time.

It was found that in heating alloys having a composition of approximately 0.1% to 1.5% silicon, 2.0% to 6.0% nickel and balance copper to the high temperatures involved in this heat treatment a skin or film develops on the metal which is termed birch bark" as it peels off, and is very That is, a film is formed on the material having a copper color. It is a very thin film, only about one or two thousandths of an inch thick, and peels off in a manner very similar to the bark of a birch tree. Hence the term birch bark eifect. The occurrence of this film or "birch bark" eiIect rendered the alloy impractical and useless.

I have discovered that the addition of certain amounts-of aluminum to this alloy will eliminate this birch bark" effect or formation of thethin skin duringthe heat treatment and renders the alloy practical as far as surface conditions are concerned. I have found if I add from approximately 0.5% to 5.0% aluminum to this alloy depending on the amount of silicon present I can effectively prevent the formation. of this skin in the heat treatment involving these high tempertemperatures involved in this treatment. The

aluminum also increases the workability of the alloy (particularly facilitating hot working) the strength, and resistance to corrosion, and for this purpose the amount of aluminum may be increased'to about 6.5%with the proportions of j silicon and nickel remaining the same. With above 6.5% aluminum the alloy rapidly becomes very hard and brittle and lacks ductility and workability so that it is unsuited for structural purposes.

Two preferred compositions which I have found very useful for certain purposes are (1) approximately 91.20% copper, 4.0% aluminum, 4.0% nickel and 0.80% silicon; and (2) 88.10% copper; 6.50% aluminum, 4.50% nickel and 0.90% silicon. Approximately the latter composition is very satisfactory for such uses as motor boat shafts and the like. 15

I have also found that the extremely high heating temperatures prescribed for the heat treatment noted produced a very coarse structure, and I discovered that the addition of given amounts of iron keeps the grain size fine. I may add iron for this purpose in amounts from 0.1% to about 3.0% to refine the grain size. It also increases the strength and workability of the alloy. In adding the iron the copper content is decreased accordingly, so that the proportions of silicon, 25 nickel and aluminum remain the same. Thus the alloy would be composed of from 0.1% to 1.5% silicon, from 2.0% to 6.0% nickel, 0.5% to 6.5% aluminum, from 0.1% to 3.0% iron and balance copper. In the specific compositions above men- 30 tioned as (1) and (2) I prefer tomake the addition of iron about 0.25%, so that these compositions as modified would be composed of approximately 90.95% copper, 4.0% aluminum, 4.0% nickel, 0.8% silicon and 0.25% iron; and approx- 35 imately 87.85% copper, 6.5% aluminum, 4.5% nickel, 0.90%si1icon and 0.25% iron.

I have found I may also further increase the workability of the alloy by adding from 0.1% to 1.0% manganese, and may increase the fluidity 40 out the metal in casting by adding from 0.1% to 1.5% tin. In each case in the addition of manganese and tin the amount of copper would be decreased accordingly with the proportions of silicon, nickel, aluminum and iron remaining as 4 above given. The preferred amount of manganese and tin to 'be added to the specific com-- positions above noted with the iron would beapproximately 0.50% for each element. If increased workability is not required the manganese may 50 be omitted. These specific compositions would then be composed of approximately 90.45% copper, 4.0% aluminum, 4.0% nickel, 0.8% silicon, 0.25% iron and 0.50% manganese; approximately 87.35% copper, 6.5% aluminum, 4.5% nickel,

0.90% silicon, 0.25% iron, and 0.50% manganese; approximateLv 89.95% copper, 4.0% aluminum, 4.0% nickel, 0.8% silicon, 0.25% iron, 0.50% manganese and 0.50% tin; and approximately 86.85% copper, 6.5% aluminum, 4.5% nickel, 0.90% silicon, 0.25% iron, 0.50% manganese, and 0.50% tin; 90.45% copper, 4.0% aluminum, 4.0% nickel, 0.8% silicon, 0.25% iron, and 0.50% tin; and approximately 87.35% copper, 6.5% aluminum, 4.5% nickel, 0.90% silicon, 0.25% iron, and 0.50% tin.

This alloy may be hot or cold rolled into plate, sheet, strip, rod and, in fact, all rolled shapes. It may be drawn through dies to rod, wire, tube and irregular shapes. It may be hot or cold forged and may be extruded into simple shapes. The alloy may be cast in sand molds or in permanent molds. It may be welded or brazed for use in the production of all types of fabricated articles by the usual welding methods. It may also be used for welding or filler rod.

The alloy has good con'osion resistance, being equal to or better than copper (depending upon the corrosive agent) and may be used to advantage wherever corrosion resistant properties are desired with the added advantages of strength, hardness and wear resistance superior to copper.

Having thus set forth the nature of my invention, what I claim is:

l. A copper base alloy composed of from 0.1% to 1.5% silicon, from 2.0% to 6.0% nickel, from 0.5% to 6.5% aluminum, from 0.1% to 3.0% iron, from 0.1% to 1.5% tin, and balance copper.

2. A copper base alloy composed of from 0.1% to 1.5% silicon, from 2.0% to 6.0% nickel, from 0.5% to 5% aluminum, from 0.1% to 3.0% iron, from 0.1% to 1.5% tin, and balance copper.

3. A copper base alloy composed oi approximately 90.45% copper, 4% aluminum, 4% nickel, 0.8% silicon,'0.25% iron, and 0.5% tin.

4. A copper base alloy composed of approximately 87.35% copper, 6.5% aluminum, 4.5% nickel, 0.9% silicon, 0.25% iron, and 0.5% tin.

5. The alloy of claim 1 to which suflieient manganese has been added to increase its workability and in amount from 0.1% to 1%.

6. The alloy of claim 2 to which suflicient manganese has been added to increase its workability and in amount from 0.1% to 1%.

'7. The alloy of claim 3 in which a portion of the copper has been replaced by suflicient manganese to increase the workability, the amount of the manganese being approximately 0.5%.

8. The alloy of claim 4 in which a portion 01 the copper has been replaced by suilicient manganese to increase the workability, the amount of the manganese being approximately 0.5%.

HERBERT C. JENNISON. 

